James Hansen

On a per capita basis, Britain is responsible for more of the carbon dioxide now in the atmosphere than any other nation on Earth because it has been burning it from the dawn of the Industrial Revolution.

The fact is fossil fuel carbon will stay in the surface climate system for millennia.

I have been described as the grandfather of climate change. In fact, I am just a grandfather and I do not want my grandchildren to say that grandpa understood what was happening but didn't make it clear.

The United States did not sign Kyoto, yet its emissions are not that different from the countries that did sign it.

Several times in Earth's history, rapid global warming occurred, apparently spurred by amplifying feedbacks. In each case, more than half of plant and animal species became extinct. New species came into being over tens and hundreds of thousands of years. But these are time scales and generations that we cannot imagine.

What makes tar sands particularly odious is that the energy you get out in the end, per unit carbon dioxide, is poor. It's equivalent to burning coal in your automobile.

The five warmest years over the last century occurred in the last eight years.

You can't turn on your television without seeing these advertisements about clean coal, clean tar sands and the claim that there's more jobs associated with fossil fuels than other industries. That's of course not true. But they're hammering that into the voters' heads.

We need to send a message to Congress and the president that we want them to take the actions that are needed to preserve climate for young people and future generations and all life on the planet.

Interference with communications of science to the public has been greater during the current administration than at any time in my career.

We are on the precipice of climate system tipping points beyond which there is no redemption.

I tend to be naive and gullible, I guess, but I try to believe that governments believe what they say.

Global warming isn't a prediction. It is happening.

Adding CO2 to the air is like throwing another blanket on the bed.

The urgency derives from the nearness of climate tipping points.

Talking nice about sun and wind and green jobs is just greenwash.

Coal is responsible for as much atmospheric carbon dioxide as other fossil fuels combined and it still has far greater reserves. We must stop using it.

It's as certain that as long as fossil fuels are the cheapest energy, we will just keep burning them.

What has become clear from the science is that we cannot burn all of the fossil fuels without creating a very different planet.

As species are exterminated by shifting climate zones, ecosystems can collapse, destroying more species.

The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.

If your child gets asthma, the fossil fuel industry doesn't pay. Or if there's a natural disaster, the bill is paid by the taxpayer, not the fossil fuel company.

Climate change is analogous to Lincoln and slavery or Churchill and Nazism: it's not the kind of thing where you can compromise.

You can't tie a rope around the ice sheet. You can't build a wall around the ice sheets.

Recent warming coincides with rapid growth of human-made greenhouse gases. The observed rapid warming gives urgency to discussions about how to slow greenhouse gas emissions.

Jail threats did not dissuade Martin Luther King - and intergenerational justice is a moral issue of comparable magnitude to civil rights.

We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.

With a fourth generation of nuclear power, you can have a technology that will burn more than 99 percent of the energy in the fuel. It would mean that you don't need to mine uranium for the next thousand years.

What we are doing to the future of our children, and the other species on the planet, is a clear moral issue.

Being at NASA and having the access to both computing capability and satellite observation capability is kind of the ideal research situation to try to understand global climate change.

Because cap and trade is enforced through the selling and trading of permits, it actually perpetuates the pollution it is supposed to eliminate.